Signaling system for electric railways.



PATENTED 116v. 20, 1906..

} L. H. THULLEN.

SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

APBLIGATION E ILED JUNE 9.1906.

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. vM N I PATENTED NOV. 20, 1906.

L.'H. THULLENY. SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

APPLICATION FILED JUNBQ. 1906.

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mechanism of -the railway-signal.

ternating current flowin in the track-circuit. As is well known, 'these'impedances R are of low ohmic resistance, so as to ermit of a free passage of direct current.

netic device is energized and the operatingmechanism moves the signal device from its horizontal to-its inclined position and retains the signal device in this position. When the saidwlectro'magnetic device is definergized,

due to the circuit including it being opened, the signal device returns to its horizontal position. I

The armature 1" of the relay R has a bias toward the contacts which it is adapted to When the coils of this relay are energized 'by an alternating current, the armature is moved away from the contacts. In this form of the invention the direct current from the source TB of a block or track sectionflows through the coil or. coils-of the re.- lay R" of its block-section; but this direct current will not cause a movement of the ar mature 1". Thus with no car or train in'the block-section the direct current from the sourceTB only energizes the relay R, which attracts its armature against its contacts-in thelocal circuit. When the direct current from the source TB is shunted from the re- Referring now to Fig. 2, the two relays R R operate a common armature r If desired, the coils of the two relays R R maybe combined so as to form a single relay. The operation of this form of the invention is the same as that describedin connection with Referring now to Fig. 3, the same signaling system is em loyed as that illustrated in Fig.'

1. In additlon the relay R is employed to control a short circuit across the rails 'ofthe block-section, which short circuit is'closed when there is an unnecessarily high or abnormal alternating-current potent al across *ing. propulsion current or to other causes.

This short circuit, which is conductors 1 2, connected with the two rails ofa block-section and with contacts 4, controlled bythe aresen as mature T of relay R is of a determinedrresistance, this being obtained by either a resistance Q or animpedance Q. The' urpose of having this circuit of a determine resistance is to prevent a-com leteshort circuit of the relay R, so, that it wi 1 not be deprived of current, and thus become inoperative to keep closed the short circuit.

derstood, I will assume that the continuous I In ,drde'r that the function of this short circuit may be unrail of the track is interrupted at a oint O in some manner whicli' interferes wit the flow of the return propulsion current along it and that a carortrain C is at the pointshown. It will be seen at once that an abnormal po tential of alternating current between the two rails of block-section A exists, at the point N, which alternating-current otential would cause more alternating pro u sion cur- 'rent to fiowthrough the coils'of t e relays R R" than was estimated uponor desirable.

This being the case, the relay R would in-' stantly respond and its armature would'en gage the contacts 3 4 to close the short circuit across the track-rails at this point, and thus 'prevent injury to the electrical apparatus connected with the track-rails of the railway.

In the short circuit for block-section A, I

have shown an impedance Q, 'whilein the short circuit for the block-section A, I have shown a resistance Q. 3

* In Fig. 4' the same .signalin system is em ployed as that illustrated in ig. 3,. as is also the short circuit across the track-iailsofa block-section which is closed when there is an unusual alternating-current potential across I the track-rails of the block-section. The armature T of'rela-y R is weighted, as m Figs. 1

and 2 ,and normally rests against the contact or contacts'of the local circuit which it controls. arranged, so that when the part/1' is moved past the vertical plane of its pivot by alter- The armature r however, is vertically nating current in'the coils of the relay R -it will drop against the contacts 3 4 of the local.

circuit and remain there until manually moved to its normal position.

, In block-section A I have also shown a relay R at the battery end of tlie' block sectmn, the coil or coils of which are in series circuit 'with, the battery TB of that blocks'ection and the trackerailsi The armature 1' of this an impedance T, the purpose of which is to limit at all times the amount of alternatin current which would tend to flow throug the battery. These 'iinpedances are of low ohmic resistanc to direct currents.

I do not limit myself to the use of two relays, as shown in Fig: 4-, as it is obvious that one relay could; be made to operate in the manner described having two windings and a common armature.

What I claim as my inventibn is- 1 1. In combination with an electric railway the trackway of which is divided to form bloclesections and serves as part of the return-path for the car-propulsion current, of 9.

source of alternating current for the-cars, and a signaling system, said system comprising a railway-signal for each block-section,- and a track-circuit for each block-section,

. which track-circuit includes a source of direct current and two relay-coils, one of which will move an armature in response to a flow of direct current and the other of which will move an armature in response onlytaa flow.

of alternating current.

2. In combination with .an electric railway the trackway of which is divided to form block-sections and serves as part of the return-path for the car-propulsion current, of a source of alternating current for the cars, and a signaling system, said systemco'inprising a railway-signal for each"'block-section, and a track-circuit for each block-section, which track-circuitincludes a source of direct current and two relays, one of which is responsive to direct current and the other ofwlnch is responsive only to alternating currents.

3. In combination with an electric railway the trackway of which is divided to form block-sections and serves as part of the return-path for the car-propulsion current, of a source of alternating current for the cars, a signaling. system for the railwav which comprises a rai way-signal for each block-section, a track-circuit for each block-section which includes a source of direct current, a relaycoil responsive to direct current and a relaycoil responsive to alternating current, and a short circuit across the track-rails of each block-section which is controlled by the relay-coil responsive to alternating currents.

4. In combination with an electric railway the trackway of whichis divided to form block-sections and serves as part of the retum-pathfor the car-propulsion current, of a spurce of alternating current for the cars, a

signaling s. tem for the railwa: which com-' prises a'ra' way-signal for each lock-section,

a track-circuit for each block-section which includes a source of-direct current, a iplay section, each track-circuit including a source of direct current, a relay-coil responsive to direct current to control the railway-signal, I

and a relay-coil responsive to alternating current to control the signal only when an abnormal alternating-current potential exists across the track-rails otablock-section.

6. In combination with an electric railway .the trackway ofg-which is'divided to form block-sections'and serves as part of the return-pathior the -car-propulsion current, a source of alternating current for the cars; a signaling system for the railwa which comprises a ra each track-circuit including .a source of dif' current, & relay-coil responsive to the direct current, a relay-coil responsive to the alternating current, and a means operated by one of the coils for establishing a short cirway-signal for each lock-section, and a track-circuiflforeach block-section,

cuit across the track-rails of a block-section.

7. In combination with an electric railway the-trackway of which is divided to form block-sections andserves as part of the return-path for the car-propulsion cm'rent; a-

source of alternating current for the cars and a signaling system for the railway which comprises a railway-signal for ca h blocksectlon and a track-circuit for eac blocksection; each track-circuit including a source of d1rect curren t," two relay-coils one respon-" sive todirect current and the other to a ternating current, and a means operated by one of the coils for establishing and maintaining until released manually a short circuit across the trackerails of a block-section.- In testiinonywhereof'l have signed my name to this s cification in the presence of two subscrib witnesses.

LOUIS H. THULLEN. Witnesses:

J. B. STBUBLE, W. L. Mc-YQANIEL.

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